The present invention relates to a method for exchanging a buzz signal between subsets of a keyphone system or in a private telephone exchange system.
One of the known methods used to transfer a received telephone signal between two different subsets of a keyphone system is to employ an additional and separate interphone set in a bridge connection or to use a special transfer switch with such a function. For example, when a secretary answers a call for another person, (i.e., her or his superior) and then needs to connect the call to a subset of that person, she or he usually uses an additional interphone, another telephone line, or another predetermined transfer means, in order to send a buzz signal to the subset of the person.
One of the drawbacks in such a transferring method is the cost of an additional interphone set. Moreover, even if there is used another internal telephone line of a keyphone system to inform the other person of the call or send a buzz signal for a transfer call, when he is engaged in his own other calling, he may not be able to receive the call or signal without properly paying attention to his own subset. This can cause a considerable inconvenience to a secretary or an operator of a keyphone system.